1. Field of the Invention
The present invention relates to a valve that is available in a fluid system such as various kinds of oil hydraulic instruments.
2. Description of the Prior Art
Heretofore, as the above-mentioned type of valves, valves nearly as shown in FIG. 11 have been generally employed. In this figure, reference character a designates a valve main body in which a cylindrical valve chamber b is formed. Reference character c designates a valve seat of circular shape, reference character d designates a valve body having a frusto-conical head portion e and a cylindrical body portion f, reference character g designates an actuating rod, reference character h designates a solenoid, reference character i designates a side port, reference character j designates an axial port, reference character k designates a spring, reference character l designates a spring receiver, reference character m designates an O-ring, and reference character n designates a slide portion. If the solenoid h is actuated, then a passageway between the valve seat c and the valve body d is opened, so that the side port i and the axial port j are communicated with each other. However, the heretofore known valve shown in FIG. 11 involves the following problems.
That is, if the valve is used over a long period of time under the pressure of a pressurized oil or the like applied through the side port i, then the balance in position of the valve body d is lost due to a side pressure applied in one direction, hence the valve body d becomes unable to engage with the valve seat c with its center correctly aligned with the center of the valve seat c, and in some cases, leakage of oil would occur. In addition, as another problem, the O-ring m at the slide portion n would be kept fixedly secured to the valve main body a after a long period of use, and so, in some cases, operation of the valve would become faulty.